[feature request] hability to configure basepath of wapi call

[mcarbonneaux]

What i whant to be added:

can be possible to add new hostConfig variable to permit to set basepath before /wapi like /< my api basepath >/wapi.

What is done actualy :

is hard coded her in https://github.com/infobloxopen/infoblox-go-client/blob/master/connector.go#L247

Why is this needed:

i need to use infoblox api behind api gateway, and i'm oblige to add /api before /wapi (/api/wapi), and actualy is not possible to configure infoblox go client to change base path of the /wapi/, like /< my api basepath >/wapi/.